1. Field of the Invention
The present invention relates generally to a navigation system for use in mobile bodies which displays map information and current positional information.
2. Description of Background Art
Mobile navigation systems that display both map information and current positional information are disclosed in Japanese Patent Publication No. Hei 5-32681. The disclosed apparatus detects the travel distance and travel direction of a mobile body or a vehicle, obtains a mobile bodys current location from the detected travel distance and travel direction, and shows a straight line connecting the obtained current location to a destination onto map information on a display unit.
The background art mobile navigation apparatus displays a straight line connecting a current location to a destination and map information, so that if a mobile body deviates from a planned travel route, it is difficult to determine whether to travel along the planned route, go to the destination without returning to the planned route or go to another point on the planned route.
It is therefore an object of the present invention to provide an mobile navigation apparatus for facilitating the decision as to which direction the mobile body should head if the mobile body has deviated from a planned travel route.
In carrying out the present invention and according to one aspect thereof, there is provided a mobile navigation apparatus comprising: current positional information generating means for detecting a current location of a mobile body and generating current positional information; map information storage means for storing map information including road information; display map information generating means for reading map information on a predetermined area from the map information storage means on the basis of the current positional information and generating display map information from the map information thus read, and display means for displaying the display map information and the current positional information; the mobile navigation apparatus further comprising: travel route planning means for planning a travel route of the mobile body on the basis of the road information; wherein, if the current location is deviated from the planned travel route, the display means shows a straight line connecting a shortest distance location on the planned travel route to the current location, the straight line making a shortest distance from the current location to the planned travel route.
Namely, according to the present invention, if a mobile body has deviated from a planned travel route, a straight line is displayed which connects a current location of the mobile body to a shortest distance location on the planned travel route which makes a shortest distance from the current location of the mobile body to the planned travel route. Consequently, the novel configuration facilitates the decision as to which direction to head the mobile body.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.